6.9.5.2 Adding LH Background as a separate AOR

Create a new AOR following the steps that you took for 3C273 i.e. Click on ``Observation"$->$``IRS Staring". Modify the target position to be offset from that of your source. For a point source, the position of the sky observations should be greater than 60 arcsecs from the source. For an extended source, the sky observations should be offset by an amount substantially larger than the angular extent of the source. Always ensure by visualizing your AORs, if the position of your sky observation is blank i.e. no bright serendipitous sources fall in your slit during the sky observation. For this particular source, we pick 12h20m06.3s, +2d02'06.9'' (J2000). Disable peak-up by selecting ``No peak-up". Select same ramp duration for the background as you selected for the sky, in this case 1$\times$240s. Figure 6.15 shows the complete AOR for the sky background. Now chain your sky background AORs and target AORs which results in them being executed as a single uninterrupted observing sequence. This can be done by Clicking on Tools$->$Group/Follow-on constraints. The Constraint Editor Tool pops up (Figure 6.16). Click on Add Chaining and enter a name for the Chain. The click on each AOR you want to chain and drag and drop the two AORs into the Constraint Editor Tool so that it looks like Figure 6.16. Then Click Apply and OK. Your background AOR has now been chained to the target AOR. The ``G" column has a check mark to indicate the Grouping of the two AORs.